Since minimally invasive surgical procedures which use an endoscopic approach are now widely used in many surgical specialties, including cardiothoracic surgery, new surgical techniques and instruments have been developed especially to assist in minimally invasive coronary artery bypass grafting (CABG) surgeries. Devices having multiple lumens and ports can be used to deliver fluid and introduce instruments, such as pressure monitors, aspirators, or filters.
Techniques used to create a cannula or catheter having multiple lumens and shapes generally include adhesive bonding, injection or compression molding, casting and machining of devices. The traditional techniques are plagued by the following problems: (1) filling tubing with adhesives is difficult to control and inconsistent, creating yield losses and quality problems, (2) injection or compression molding requires costly tooling and cannot form specific shapes, and (3) machining is labor-intensive and cannot form certain shapes. A need therefore exists for methods which provide easy and consistent means of forming cannulas or catheters which have multi-layered tubing cross-sections, and for the resulting devices.